The objectives of this study are to investigate the interaction of some important airborne environmental pollutants with selected areas of liver metabolism in different species of animals. The first pollutant to be studied will be carbon monoxide. The experiments will be designed to see whether inhaled carbon monoxide can affect the heme containing hepatic cytochrome P-450 and if so whether a correlation with blood COHb can be made. Consequent to an alteration in cytochrome P-450, an alteration in the activities of the cytochrome P-450 dependent microsomal enzymes can be expected. The effects of carbon monoxide will be compared to the effects of lowered bl@od pO2 equivalent to that produced by CO. If changes following acute exposure to CO are observed, then experiments will be designed to study the effect of chronic exposure to see if adaptation takes place. Adaptation as demonstrated by an increase in blood hemoglobin and hematocrit will be expected and will be compared with cytochrome P-450 loevels and microsomal activities. The development of a model system showing the interaction of inhaled CO with drug metabolism lends itself to a variety of physiologic conditions from which it can be studied. These may include the effects of exposure to CO under hypoxic conditions (altitude), exposure of the pregnant animal and the subsequet effect on the fetus, and exposure of the newborn.